Isolation Of Heavy Metal Resistance Microorganism And Study On Its Biosorption To Zn²⁺, Cd²⁺ And Cr (VI)

Because of human activities and natural migration, heavy metal pollution often appears in a variety of environments, which threat human health and ecological balance. Microbial remediation is a new technique to clean up the environments contaminated by heavy metals. Depending on the sorption and accumulation of microorganisms, a large amount of heavy metals can be transferred or transformed in those environments, so that their toxicity can be lower down.From Huludao Yangjiazhangzi Mo Tailings Reservoir soil, the thesis isolated WT6-5, which was identified as Rhodotorula sp. The experiment got the optimum culture condition of WT6-5 in LB:the carbon source was glucose, the nitrogen source was microzyme, the culture time was 36 hours, the pH value of culture medium was about 5.0, the culture temperature was 23-28℃, the culture NaCl concentration was 5g/L.The thesis did a research on the influence of Zn2+,Cd2+ and Cr (VI) to WT6-5's growth. The results showed that WT6-5's growth was better at a low concentration than at zero concentration, while worse at a high concentration. The toxicity order to WT6-5 was Cd2+>Zn2+> Cr (VI)The thesis mainly studied on WT6-5's biosoption and accumulation of Zn2+,Cd2+ and Cr (VI). The results showd that WT6-5 couldn't adsorb and accumulate Cr(VI), but could adsorb and accumulate Zn2+ and Cd2+. The accumulation rates are 20% and 80% separately. The biosoption rates are 40% and 70% separately. The optimum biosoption condition of WT6-5 was got:the culture time was 3 days, the biosoption time was 15 minutes, the biomass quantity was 18mg/mL, pH value was 7-9. Growing with the initial concentration of heavy metals, the biosoption rates gradually reduced. Presence of other heavy metals would affect the accumulation rate and the rate of absorption. Analysis by IR spectroscopy, hydroxide, acylamide, carboxyl, C-N, carbonyl and sulfur carbonyl are main biosoption spots. Analysis by SEM, heavy metal ions was absorbed by cytoderm after destroying capsule.The results of the whole study showed that WT6-5 can be accumulated and adsorb Zn2+ and Cd2+, which was a practical ability for future use. Key words:Heavy metal, Rhodotorula sp. Biosorption, Accumulation...